The human heart is the muscle that is responsible for pumping blood throughout the vascular network. Veins are vessels that carry blood toward the heart while arteries carry blood away from the heart. The human heart consists of two atrial chambers and two ventricular chambers. Atrial chambers receive blood from the body and the ventricular chambers, which include larger muscular walls, pump blood from the heart. A septum separates the left and the right sides of the heart. Movement of the blood is as follows: blood enters the right atrium from either the superior or inferior vena cava and moves into the right ventricle. From the right ventricle, blood is pumped to the lungs via pulmonary arteries to become oxygenated. Once the blood has been oxygenated, the blood returns to the heart by entering the left atrium, via the pulmonary veins, and into the left ventricle. Finally, the blood is pumped from the left ventricle into the aorta and the vascular network.
For the vast majority of the population, the events associated with the movement of blood happen without circumstance. However, for many people the heart fails to provide adequate pumping capabilities. These heart failures may include congestive heart failure (commonly referred to as heart disease), which is a condition that results in any structural or functional cardiac disorder that impairs the ability of the heart to fill with or pump blood throughout the body. Presently, there is no known cure for heart disease and long-term treatment is limited to a heart transplant. With only a little over 2,000 patients receiving a heart transplant each year, and over 16,600 more on the waiting list for a heart, there is a persisting need for a cure or at the minimum a means of improving the quality of life of those patients on the waiting list.
One such means of bridging the time gap while awaiting a transplant is a circulatory assist system. Circulatory assist systems may also be utilized as a destination therapy for individuals not eligible for a heart transplant. These systems, originally envisioned over thirty years ago, provide assistance to the heart by way of a mechanical pump. In this way, blood is circulated throughout the vascular network despite the diseased heart tissue. Traditionally, these circulatory assist systems include an implantable or extracorporeal pump, a controller (internal or external), and inflow and outflow tubes connecting the pump to the heart and the vascular network. Food and Drug Administration (FDA) approved circulatory assist systems can partially relieve symptoms of breathlessness and fatigue associated with severe heart failure and drastically improve quality of life.
The wait time for receiving a heart transplant may be substantial. Therefore, circulatory assist systems, and particular the pumps driving them, must be designed for longevity. Furthermore, it is desirable to provide an ideal and advantageous flow of blood therethrough without damaging the blood. There is therefore a need in the art for a pump and a circulatory assist system which experiences low amounts of inter-component friction during operation and causes less damage to blood than other pumps known in the art.